Drawing instrument.



No. 761,197. PATENTED MAY 31, 1904. W. S. BOWNESS & G. L. JONES. DRAWING INSTRUMENT.

APPLIOATION FILED SEPT. 28,1903.-

N0 MODEL.

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WALTER SCOTT BOWNEss AND Patented May 31, 1904.

PATENT OEEIOEo CLARENCE LEWIS JONES, OE MONCTON, CANADA.

DRAWING INSTRUMENT.

sPECIFICATIoN forming pare of Letters Patent 10.761,19'7, dated'May 31', 1904. I Application 165. September Z8, 1903. Serial No. 174,877. (No model.)

T0 all whom it may concern;

Be it known that we, WALTER SCOTT Bow- NEss and CLARENCELEWIS JONES, subjects of the King of Great Britain, residing at Moncton, in the county of Westmoreland, inthe Province of New Brunswick, Canada, have invented certain new and useful Improvements in Drawing Instruments, of which the following is a specification.

Our invention relates to improvements in drawing instruments; and the object of the invention is to devise a curve-tracer which shall facilitate the work of preparation of drawings in which the curves represent the arc of a circle of dimensions too great to be correctly made from the instruments as at present provided; and it consists, essentially, of a frame having suitable bearings therein, apair of wheels independently journaled toward one end of said frame, a guiding-wheel journaled at the other end, mechanism controlling the line of direction of the guidingwheel, and indicating means for setting the guiding-wheel, the various parts being constructed in detail as hereinafter more particularly described.

Figure 1 is a plan view of our instrument from above. Fig. 2 is' a longitudinal section of our instrument. Fig. 3 is a plan view of our instrument from below. Y Fig. 4; is a plan view from above, showing another form of gear mechanism. Fig. 5 isa detail of a pencil used in describing the arc. Fig. 6 is a crosssectional view through vthe bearings in the fore part of the frame.

Like characters of reference indicate corresponding parts in each figure.

a is the frame, having the bearings Z and cin the rear portion thereof. The bearings and y c are entirely independent one of the other and have journaled therein the rods CZ and e, respectively, on which are iXedly mounted the wheels fand g, preferably having a knurled edge. It will thus be seen that the wheels f and g turn independently oneof theother.

/L is a ring supported slightly above the rear part of the frame, as shown at e' and j'.

is an indicating-wheel turning on the central upward projection Z from the frame inside thev ring it and suitably held in place on said central projection l by the cap-screw m, introduced in a correspondingly-threaded orifice in said central projection Z.

' n is a pinion securely attached to the under side of the indicating-Wheel lo and surrounding the central projection l and turning with the said indicating-wheel 1.

ois a clamp designed to holdy the indicating-wheel in any desired position. The ring It is divided into degrees or such measurements as desirable, and on the indicating-wheel k is a pointer or indicating-mark p, designed to point variously to the degrees on the ring L.

Q is a segmental gear having a radial arm r forming part thereof or securely attached thereto and provided with an annular end s, concentric with the segmental gear. The annular end s has two lugs t projecting upwardly from its reduced lower portion u.

o represents bearings depending from the reduced lower portion u of the annular end s and xedly secured thereto or forming part thereof.

w is a rod journaled in the bearings o and having the wheel mounted thereon.

z/ is is the fore part of the frame a, circularly formed to receive the correspondinglydimensioned reduced lower portion u of the annular end s and having a 'supporting-ledge atherefor.

2 represents slots through the ledge a, 'designed to allow the passage of the lugs when the annular end s is introduced,into'the'circularly-formed fore part of theframe, and on the turning into place ofthe said annular end in the fore part of the frame the lugs pass under the ledge e and hold the parts together, and the segmental gear qand the pinion a are brought to mesh. j'

3 represents rods threaded at oneend and designed to screw into the correspondinglythreaded orifice 4 in the bearings C. j

5 is a ring designed to slide over the rods 3 and having a set-screw 6 and a projecting lug 7, to which is pivotally attached the barrel 8 or pencil-holder.

9 is a spring securely attached to the ring 5 and bearing on the barrel 8 to hold the point of the pencil 410 in contact with the paper.

In Fig. 1 we have shown another form of gear mechanism and means of indicating the line of direction for the guiding-wheel. 11 is a rod journaled in suitable bearings 12 on the top of the frame a and having a thumb-wheel 13 at its upper end and a worm 14 intermediate of its length between the bearings. 15 is an indicating-finger suitably secured to the frame a and centrally situated. 16 is asegmental gear divided into degrees or suitable measurements pointed out variously by the fingerv 15. Otherwise the construction of this form of the instrument is the same as described in the foregoing. Y

Having described the various parts involved in our invention in detail, we shall now more particularly explain the utility and operation. In the preparation of plans for large engineering Works the describingof a curve-say, for example, on a line of railway-has involved certain difficulties and to some extent has been a matter of guesswork. u The instrument which has, been described herein overcomes the diiculties in such work, as it is provided with a mathematically-arranged dial on vwhich the measurements or degrees, according to the method adopted in practice, maybe placed., For instance, in the instrument as described the ring /z` is supposed to be divided into degrees, and the indicatingwheel 7c is provided with a'iinger or markingpoint which may be set to any degree on the dial, the user first ascertaining the degrees necessary to obtain the information as to dimensions, by means of which the indicatinglinger may be set on the dial. This is purely a technical matter and need not be described at any lengthherein, as the dial of the instrument may be arranged in many ways to suit different work in which it may be employed. When the indicating-lingerl points, say, ten, twenty, or thirty degrees off the center, the guiding-wheel m will be swung a corresponding degree.. It will thus be seen that no matter where the measurements or degrees are placed, either on the ring L, having the pinion securely attached underneath, or on the segmental gear, the results will be the same as regards the direction in which the guiding-wheel may be set. The arm r being fixedly secured or forming' part of the said segmental gear and the annular end s. being concentric with the said segmental gear and having the bearings of the wheel iixedly .attached thereto, the said wheel .fr must al- Ways follow circumferentially with the segmental gear. y The pencil is attached to one or other of the rods 3 in the manner hereinbefore described, and consequently must follow the direction taken by the guiding-wheel and allowance must be made in setting the instrument for the larger or smaller circle described than would be the case if the mark was made directly by the wheel.

The use of the instrument is extremely simple, for, after setting, the carriage issimply moved along the paper, ,starting the pencil at the point where the curve is designed to emanate and iinishing at the proper point of termination.

What we claim as our invention is- 1. In a drawing instrument, the combination with a frame havingaguiding-wheel journaled at one end thereof, a pair of wheels independently journaled one of the other toward ,the other end of said frame, a gearwheel journaled on a pintle projecting upwardly from the frame, a coacting segmental gear, a radial arm extending from said segmental gear, for turning the guiding-wheel, and indicating means for setting said guiding-wheel, as and for the purpose specified.

2. In a drawing instrument, the combination with a frame having a guiding-wheel journaled at one-end thereof, a pair of wheels independently journaled one of the other toward the other end of said frame, a gearwheel journaled on a pintle projecting upwardly from the frame, a dial raised from the frame, an indicating-wheel turning in said dial and secured to said gear-wheel, a coacting segmental gear, a radial arm extending therefrom, for turning said guiding-wheel, as and-for the purposespecified.

3. In a drawing instrument, lthe combination with a frame having a guiding-wheel journaled at one end thereof, a pair of wheels independently journaled one of the other'toward the other end of said frame,` a gearwheel journaled on a pintle projecting upwardly from the frame, a dial raised from the frame, an indicating-wheel turning in said dial and secured vto said gear-wheel, means for arresting movement of gear, ay coacting segmental gear, and a radial arm extending therefrom, for turning said guiding-wheel, as and for the purpose specified. 4. In a drawing instrument, the combination with a frame having a horizontal Vbearing at one end thereof, of a segmental gear having a radial arm terminating in a ring, journaled in the aforesaid horizontal bearing and concentric with said gear, a set of bearings xedly attached to said ring, an axle journaled in said bearings on the ring, a wheel ixedly mounted on said axle, a pairof wheels independently journaled toward the other end of the frame, and a gear suitably journaled and meshing with the said segmental gear, as and for the purpose specified. Y

5. In a drawing instrument, ythe combination with a frame having a guiding-wheel journaled at one end thereof, a pair of wheels independently journaled one or' theother toward the other end of said frame, mechanism controlling the line of direction of the guid- IOO IIO

ing-wheel, rods projecting outwardly and at right angles to the direction of the guidingwheel from the Journals thereof, and amarkl ing device on one of the said rods, as and for the purpose specified.

6. In a drawing instrument, the combination with a frame having a guldlng-wheel jour- .naled at one end thereof, a pair of wheels independently journaled one of the other toward the other end of said frame, mechanism controlling` the line of direction of the guiding-wheel, rods projecting outwardly and at right angles to the plane of the guiding-wheel 

